[Python-checkins] cpython: Issue #15026: utf-16 encoding is now significantly faster (up to 10x).
antoine.pitrou
python-checkins at python.org
Fri Jun 15 22:18:31 CEST 2012
http://hg.python.org/cpython/rev/acca141fda80
changeset: 77448:acca141fda80
user: Antoine Pitrou <solipsis at pitrou.net>
date: Fri Jun 15 22:15:23 2012 +0200
summary:
Issue #15026: utf-16 encoding is now significantly faster (up to 10x).
Patch by Serhiy Storchaka.
files:
Include/unicodeobject.h | 4 +-
Misc/NEWS | 3 +
Objects/stringlib/codecs.h | 64 +++++++++++++++++++
Objects/unicodeobject.c | 86 ++++++++++---------------
4 files changed, 105 insertions(+), 52 deletions(-)
diff --git a/Include/unicodeobject.h b/Include/unicodeobject.h
--- a/Include/unicodeobject.h
+++ b/Include/unicodeobject.h
@@ -188,9 +188,9 @@
(((((Py_UCS4)(high) & 0x03FF) << 10) | \
((Py_UCS4)(low) & 0x03FF)) + 0x10000)
/* high surrogate = top 10 bits added to D800 */
-#define Py_UNICODE_HIGH_SURROGATE(ch) (0xD800 | (((ch) - 0x10000) >> 10))
+#define Py_UNICODE_HIGH_SURROGATE(ch) (0xD800 - (0x10000 >> 10) + ((ch) >> 10))
/* low surrogate = bottom 10 bits added to DC00 */
-#define Py_UNICODE_LOW_SURROGATE(ch) (0xDC00 | (((ch) - 0x10000) & 0x3FF))
+#define Py_UNICODE_LOW_SURROGATE(ch) (0xDC00 + ((ch) & 0x3FF))
/* Check if substring matches at given offset. The offset must be
valid, and the substring must not be empty. */
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@
Core and Builtins
-----------------
+- Issue #15026: utf-16 encoding is now significantly faster (up to 10x).
+ Patch by Serhiy Storchaka.
+
- Issue #11022: open() and io.TextIOWrapper are now calling
locale.getpreferredencoding(False) instead of locale.getpreferredencoding()
in text mode if the encoding is not specified. Don't change temporary the
diff --git a/Objects/stringlib/codecs.h b/Objects/stringlib/codecs.h
--- a/Objects/stringlib/codecs.h
+++ b/Objects/stringlib/codecs.h
@@ -562,4 +562,68 @@
#undef STRIPPED_MASK
#undef SWAB
#undef LONG_PTR_MASK
+
+
+Py_LOCAL_INLINE(void)
+STRINGLIB(utf16_encode)(unsigned short *out,
+ const STRINGLIB_CHAR *in,
+ Py_ssize_t len,
+ int native_ordering)
+{
+ const STRINGLIB_CHAR *end = in + len;
+#if STRINGLIB_SIZEOF_CHAR == 1
+# define SWAB2(CH) ((CH) << 8)
+#else
+# define SWAB2(CH) (((CH) << 8) | ((CH) >> 8))
+#endif
+#if STRINGLIB_MAX_CHAR < 0x10000
+ if (native_ordering) {
+# if STRINGLIB_SIZEOF_CHAR == 2
+ Py_MEMCPY(out, in, 2 * len);
+# else
+ _PyUnicode_CONVERT_BYTES(STRINGLIB_CHAR, unsigned short, in, end, out);
+# endif
+ } else {
+ const STRINGLIB_CHAR *unrolled_end = in + (len & ~ (Py_ssize_t) 3);
+ while (in < unrolled_end) {
+ out[0] = SWAB2(in[0]);
+ out[1] = SWAB2(in[1]);
+ out[2] = SWAB2(in[2]);
+ out[3] = SWAB2(in[3]);
+ in += 4; out += 4;
+ }
+ while (in < end) {
+ *out++ = SWAB2(*in);
+ ++in;
+ }
+ }
+#else
+ if (native_ordering) {
+ while (in < end) {
+ Py_UCS4 ch = *in++;
+ if (ch < 0x10000)
+ *out++ = ch;
+ else {
+ out[0] = Py_UNICODE_HIGH_SURROGATE(ch);
+ out[1] = Py_UNICODE_LOW_SURROGATE(ch);
+ out += 2;
+ }
+ }
+ } else {
+ while (in < end) {
+ Py_UCS4 ch = *in++;
+ if (ch < 0x10000)
+ *out++ = SWAB2((Py_UCS2)ch);
+ else {
+ Py_UCS2 ch1 = Py_UNICODE_HIGH_SURROGATE(ch);
+ Py_UCS2 ch2 = Py_UNICODE_LOW_SURROGATE(ch);
+ out[0] = SWAB2(ch1);
+ out[1] = SWAB2(ch2);
+ out += 2;
+ }
+ }
+ }
+#endif
+#undef SWAB2
+}
#endif /* STRINGLIB_IS_UNICODE */
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -5359,26 +5359,18 @@
const char *errors,
int byteorder)
{
- int kind;
- void *data;
+ enum PyUnicode_Kind kind;
+ const void *data;
Py_ssize_t len;
PyObject *v;
- unsigned char *p;
- Py_ssize_t nsize, bytesize;
- Py_ssize_t i, pairs;
- /* Offsets from p for storing byte pairs in the right order. */
-#ifdef BYTEORDER_IS_LITTLE_ENDIAN
- int ihi = 1, ilo = 0;
+ unsigned short *out;
+ Py_ssize_t bytesize;
+ Py_ssize_t pairs;
+#ifdef WORDS_BIGENDIAN
+ int native_ordering = byteorder >= 0;
#else
- int ihi = 0, ilo = 1;
-#endif
-
-#define STORECHAR(CH) \
- do { \
- p[ihi] = ((CH) >> 8) & 0xff; \
- p[ilo] = (CH) & 0xff; \
- p += 2; \
- } while(0)
+ int native_ordering = byteorder <= 0;
+#endif
if (!PyUnicode_Check(str)) {
PyErr_BadArgument();
@@ -5391,53 +5383,47 @@
len = PyUnicode_GET_LENGTH(str);
pairs = 0;
- if (kind == PyUnicode_4BYTE_KIND)
- for (i = 0; i < len; i++)
- if (PyUnicode_READ(kind, data, i) >= 0x10000)
+ if (kind == PyUnicode_4BYTE_KIND) {
+ const Py_UCS4 *in = (const Py_UCS4 *)data;
+ const Py_UCS4 *end = in + len;
+ while (in < end)
+ if (*in++ >= 0x10000)
pairs++;
- /* 2 * (len + pairs + (byteorder == 0)) */
- if (len > PY_SSIZE_T_MAX - pairs - (byteorder == 0))
+ }
+ if (len > PY_SSIZE_T_MAX / 2 - pairs - (byteorder == 0))
return PyErr_NoMemory();
- nsize = len + pairs + (byteorder == 0);
- bytesize = nsize * 2;
- if (bytesize / 2 != nsize)
- return PyErr_NoMemory();
+ bytesize = (len + pairs + (byteorder == 0)) * 2;
v = PyBytes_FromStringAndSize(NULL, bytesize);
if (v == NULL)
return NULL;
- p = (unsigned char *)PyBytes_AS_STRING(v);
+ /* output buffer is 2-bytes aligned */
+ assert(((Py_uintptr_t)PyBytes_AS_STRING(v) & 1) == 0);
+ out = (unsigned short *)PyBytes_AS_STRING(v);
if (byteorder == 0)
- STORECHAR(0xFEFF);
+ *out++ = 0xFEFF;
if (len == 0)
goto done;
- if (byteorder == -1) {
- /* force LE */
- ihi = 1;
- ilo = 0;
- }
- else if (byteorder == 1) {
- /* force BE */
- ihi = 0;
- ilo = 1;
- }
-
- for (i = 0; i < len; i++) {
- Py_UCS4 ch = PyUnicode_READ(kind, data, i);
- Py_UCS4 ch2 = 0;
- if (ch >= 0x10000) {
- ch2 = Py_UNICODE_LOW_SURROGATE(ch);
- ch = Py_UNICODE_HIGH_SURROGATE(ch);
- }
- STORECHAR(ch);
- if (ch2)
- STORECHAR(ch2);
+ switch (kind) {
+ case PyUnicode_1BYTE_KIND: {
+ ucs1lib_utf16_encode(out, (const Py_UCS1 *)data, len, native_ordering);
+ break;
+ }
+ case PyUnicode_2BYTE_KIND: {
+ ucs2lib_utf16_encode(out, (const Py_UCS2 *)data, len, native_ordering);
+ break;
+ }
+ case PyUnicode_4BYTE_KIND: {
+ ucs4lib_utf16_encode(out, (const Py_UCS4 *)data, len, native_ordering);
+ break;
+ }
+ default:
+ assert(0);
}
done:
return v;
-#undef STORECHAR
}
PyObject *
--
Repository URL: http://hg.python.org/cpython
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